Report of Expert Meeting on Factor Viii Products and Inhibitor Development

SUMMARY An EMEA expert meeting on FVIII products and inhibitor development was held on 28 February to 2 March 2006 to provide a forum to discuss the international standardisation and harmonisation of requirements for clinical studies on FVIII inhibitor development in haemophilia A patients. The long-term objective is to collect comparable clinical data on the immunogenicity of recombinant and plasma-derived FVIII products in future. The expert meeting was divided into an open session, where haemophilia treaters, competent authorities from EU, US, Japan and Canada, representatives from the International Society for Thrombosis and Haemostasis (ISTH), the World Health Organisation (WHO), patient organisations and industry discussed clinical study requirements, and a restricted session, where EU competent authorities discussed the outcome of the meeting. A number of issues were discussed relating to: current data on FVIII products and inhibitor development, FVIII inhibitor measurement, clinical relevance of FVIII inhibitor occurrence, clinical study design, registries, risk management, post-marketing studies and pharmacovigilance. This report summarises the discussions held at the open sessions. Conclusions drawn from these discussions in the restricted session and at the Blood Products Working Party (BPWP) meetings in June and September 2006 are listed at the end of the report. The outcome of these discussions will be taken into account in the revision of the Notes for Guidance on clinical investigation of human plasma-derived and recombinant FVIII and FIX products and the corresponding core Summaries of Product Characteristics (SPCs). In addition, on recommendation of the experts, the Committee for Human Medicinal Products (CHMP) has contacted the ISTH SSC Subcommittee for FVIII and FIX in June 2006 regarding two topics: the FVIII inhibitor assay and the development of common data sets for registries. The activities of the ISTH SSC Subcommittee in these two areas are complementary to the work of the CHMP/BPWP/Pharmacovigilance Working Party (PhVWP) and national competent authorities.